Heney woodboeough



No. 753,025. PATENTED FEB. 23,1904. H. WOODBOROUGH.

PROTRAGTOR.

AFPLIGATION FILED JULY 2 1903.

N0 MODEL. -2 SHEETS-SHEET l.

PATENTED FEB. 23, 1994. H. WOODBOROUGH.

PROTRAGTQR. APPLIGATION FILED JULY 2, 1903.

2 SHEETS-SHEET 2 N0 MODEL.

m: mums versus no. PHOTO-Undo. WASHINGTON a. c.

Patented February 23, 1904.

UNITED "STATES PATENT OFFICE.

HENRY VVOODBOROUGH, NEW YORK, N. Y.

PROTRAOTOR.

SPECIFICATION forming part of Letters Patent No. 753,025, dated February23, 1904.

Application filed m 2, 1909. Serial No. 164,020. (No model.)

I0 aZZ whom it may concern:

Be it known that I, HENRY Wooneonouema subject of the King of England,residing in the borough of Brooklyn, city and State of New York, haveinvented an Improvement in Protractors, of which the following is aspecification.

My invention relates particularly to the class of adjustablebevel-protractors such as are employed by artisans or workers in woodand metal. Heretofore instruments of this class have comprised a stockand a straight-edge, a dial and indicator, a revoluble arm turning withsaid indicator, and a slidable blade attached to said revoluble arm, therelation of the blade and straight-edge giving the angle. With theseinstruments it is impossible to read and Work with angles less thanabout twenty degrees; and the object of my inventionis to'produceabevel-protractor with which the very smallest angles readable upon thedial may be measured.

In carrying out my invention and in combination with a protractor ofWell-known form having a blade slidably-connected thereto and adapted toturn therewith I employ a second blade interchangeable on the indicatorwith the aforesaid blade and adapted to itself receive said blade atright angles thereto and coacting with the said straight-edge and meansfor securely holding the indicator and the respective blades in thedesired position.

In the drawings, Figure l is an elevation of my improvedbevel-protractor to the Brown & Sharpe universal bevel protractor. Fig.2 is an enlarged'transverse section on line w 00, Fig. 1. Fig. 3 is aview of the inner face of one of the end plates connected to the blade.Fig. 4 is an elevation illustrating a modification of my invention asapplicable to the Starrett protractor. Fig. 5 is an elevation of thereverse side of the end of the blade shown in Fig. 4, and Fig. 6 is anedge view of the same.

(t represents a stock to which, and preferably integral therewith, astraight-edge b is secured, and in Fig. 1 c is adial graduated indegrees on one face of the stock a. An indicator-disk (Z is revolublymounted on this face of the dial and has an arm a connected with it, andthere is a thumb-screw 2, by which I prefer to employ two plates 5 and6, secured thereto by screws 7. The inner face of the plate 6 isrecessed at 8 to receive a clamp member or frame 9, having a tongue 10along one of its sides. A square aperture is formed in the clamp member9 to receive a screw-head 11, whose shank passes through the plate 6 andis connected to a thumb-screw 12. The shank of the screw-head 11 is oficenter, so that turning the thumb-screw 12 imparts an eccentric movementto the head 11 and causes areciprocating sliding movement of the clampmember or frame 9 within the recess 8. The blade it, havingalongitudinal groove 13 therein, is adapted to be received between theplates 5 and 6 at the end of the blade f and at right angles thereto,the tongue 10 engaging the groove 13 and the blade coacting with theprotractor. This blade 5 may be the blade employed ordinarily with thisform of protractor and removed from engagement with the arm 6 toengagement with the blade f.

The clamping construction hereinbefore described as employed at the endof the blade f may be employed at the end of the arm 6, or any suitableclamping devices may be used at both these places. It will be readilyunderstood that the blade f is slidably adjustable in the end of the arm6 and the blade it is slidably adjustable in the end of the blade f andthat both these blades may be held in place in any desired position.

Referring to Fig. 4, (4' represents the stock, I) the straight-edge, andc the dial, which in this instance is revolubly mounted in the stock aand provided with an arm or limb d. The limb cl is adapted to receivethe longitudinally-grooved blade f, which is slidably adjustable in saidlimb and may be held in any desired position therein by a thumb-screw 14or any other suitable means.

As shown in Figs. 4, 5, and 6, the end of the blade f may be made with ahead recessed at pin 2', one of whose ends engages the groove in theblade in. The other end of the pin i is threaded and provided with athumb-screw 16,-

by means of which the blade k may be clamped and held in position atright angles to the blade f. The blade h may be the blade employedordinarily with this form of protractor and removed from engagement withthe part 0? to engagement with the head of the blade f".

I claim as my invention 1. A bevel-protractor comprising a stock havinga straightedge, a revoluble arm, a grooved blade slidable in said arm,means for clamping said blade to said arm,. a second grooved bladeslidable in the end of the aforesaid blade and coacting with the saidstraightedge, and means for clamping the said second blade in position.

2. A bevel-protractor, comprising a stock having a dial in degrees onone side thereof and a straight-edge, a revoluble indicator mounted onsaid stock, an arm connected to said indicator, a grooved blade slidablein said arm, means for clamping said blade to said arm, a second groovedblade slidable in the end of the aforesaid blade and coacting with thesaid straight-edge, and means for clamp- HENRY WOODBOROUGH.

Witnesses:

GEO. T. PINCKNEY, S. T. HAVILAND.

